The present invention relates to a camera having a built-in flash unit, and more particularly, the present invention relates to a built-in flash unit of a camera that rotates between a housed position and a use position.
FIGS. 7-9 (PRIOR ART) illustrate a prior art single lens reflex camera 40 having a built-in flash unit 50. As illustrated in FIG. 9 (PRIOR ART), built-in flash unit 50 includes a light emitting unit 51 housed and supported in an upper casing 52 and a lower casing 53. As illustrated in FIGS. 7 and 8 (PRIOR ART), camera 40 has a front surface side 42, a back surface side 44, a left side 47, and a right side 49. Upper casing 52 is rotatably supported on a shaft support unit (not shown) located near back surface side 44. As a result, flash unit 50 can be rotated by upper casing 52 between a housed position, within camera 40, as illustrated in FIG. 9 (PRIOR ART), and a use position, extending outside camera 40, as illustrated in FIG. 8 (PRIOR ART).
As illustrated in FIG. 9 (PRIOR ART), light emitting unit 51 includes a light source, such as a xenon tube 51a, that is protected from the outside environment by a protector 51c located in front of xenon tube 51a. A reflector 51b, located in light emitting unit 51, emits light to help ensure that illumination from xenon tube 51a is uniform.
A pentaprism 4 allows light which passes through a photographic lens 46 to pass through to a viewfinder eyepiece unit 70. Pentaprism 4 includes a first roof surface 4a, a second roof surface 4b, and a third reflecting surface 4c. Third reflecting surface 4c enables light reflected by roof surfaces 4a and 4b to pass to eyepiece unit 70.
Flash unit 50 is rotated by upper casing 52 to the housed position illustrated in FIG. 9 (PRIOR ART) when built-in flash unit 50 is not in use. As illustrated in FIG. 9 (PRIOR ART), when camera 40 is in the housed position, light emitting unit 51 is positioned along a front, top position of pentaprism 4. By engaging a release switch (not shown) or performing some other predetermined operation when camera 40 is in the housed position, upper case 52 rotates in a clockwise rotary direction with respect to camera 40 and flash unit 50 rotates to the use position illustrated in FIGS. 7 and 8 (PRIOR ART). By positioning flash unit 50 in the use position, a flash photography function of camera 40 is enabled.
A photographic optical axis for performing a photographic operation extends from camera 40 to a photographic subject. In prior art single lens reflex cameras, the shaft support unit extends from left side 47 to right side 49 in a direction perpendicular to the photographic optical axis. Flash unit 50 rotates about the shaft support unit at right angles to the photographic optical axis. As illustrated in FIG. 9 (PRIOR ART), when flash unit 50 is rotated to the housed position, light emitting unit 51 is positioned along a front top portion of pentaprism 4. As illustrated in FIGS. 8 and 9 (PRIOR ART), a protection member 61 is needed to protect light emitting unit 51 from being damaged when in the housed position. Protection member 61, located at an upper portion of front surface side 42 of camera 40, extends outward from front surface side 42, increasing the overall size of camera 40. This increased size of camera 40, particularly an increased depth, makes camera 40 less compact and portable, and more difficult to store.
In order to obtain a proper distribution of luminous intensity from light emitting unit 51, upper casing 52 must be fully rotated so that light emitting unit is parallel to the photographic optical axis. Therefore, if upper casing 52 is positioned at any point between the use and the housed position during a photographic operation, the luminous intensity is corrupted, which can result in improperly illuminated photographs and a lessening of picture quality.